<p><i>Trichoderma frianum</i> sp. nov., a wood-inhabiting species from India, is described based on morphological characteristics and molecular phylogenetic analyses. This taxon is congruent with the morphological species concept of <i>T. harzianum </i>sensu lato, characterized by pyramidal conidiophores and cruciate phialidic whorls with fewer than five phialides. However, it differs by producing verticils that bear up to seven divergent phialides. Phylogenetic analyses based on a&#xa0;combined dataset of the translation elongation factor 1-alpha (<i>tef1</i>) and RNA polymerase II second-largest&#xa0;subunit (<i>rpb2</i>) gene regions confirmed the placement of <i>T. frianum</i> within the <i>T. harzianum</i> species complex (THSC) of the <i>Harzianum</i> clade. This species forms a sister lineage to <i>T. anaharzianum</i>, <i>T. neotropicale</i>, <i>T. lixii</i>, <i>T. xixiacum</i>, and <i>T. lentinulae</i>, with the pairwise homoplasy index (PHI) test supporting their classification as distinct species. Comparative sequence analyses revealed that <i>T. frianum</i> possesses unique <i>tef1</i> and <i>rpb2</i> sequences that do not meet the ∃!(<i>rpb2</i>₉₉ ≅ <i>tef1</i>₉₇) standard for known species, fulfilling the criteria of the International Commission on <i>Trichoderma</i> Taxonomy (ICTT) for new species delineation. However, deviations from the <i>tef1</i> and <i>rpb2</i> thresholds were observed in some comparisons within THSC and are discussed. Functionally, <i>T. frianum</i> exhibited strong antagonistic activity against major <i>Eucalyptus</i> pathogens and showed robust growth under high-salinity conditions in vitro, suggesting its potential for biocontrol and stress-resilient forestry systems.</p>